linux-kernel - USB autosuspend causing trouble with bluetooth

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Message-ID: <CABVT_gf-rx0ymvtCrCotkO5=qoDifG1yAMg8U_aTgXEN=x6gvg@mail.gmail.com>
Date:	Sun, 18 Jan 2015 17:30:36 +0400
From:	Kirill Elagin <kirelagin@...il.com>
To:	linux-kernel@...r.kernel.org
Cc:	marcel@...tmann.org
Subject: USB autosuspend causing trouble with bluetooth

Hello,

Recently I started having issues with my Apple Magic Trackpad and I
realised that the problem was with autosuspend. Whenever I have `auto`
in `power/control` of my BT adapter, `btmon` shows no packets,
nothing. As soon as I `echo on`, all the missing packets arrive.

The situation looks very similar to this thread:
https://lkml.org/lkml/2014/4/2/574.
As suggested, I tried `hci-tester` and I’m attaching the complete
output, but, I guess, the interesting part is that with `on` in
`power/control` I get:

~~~~
Inquiry (LIAC)      Passed      10.254 seconds
~~~~

and with `auto` I get:

~~~~
Inquiry (LIAC)        Timed out   30.365 seconds
~~~~

This is Acer 4810TG laptop with BCM2046. The kernel is 3.17.7, but I’m
pretty sure I was also seeing this on 3.18.1. Bluez is 5.25.

P.S. Please, CC me as I’m not a subscriber.

View attachment "hci-tester_on.log" of type "text/plain" (4891 bytes)

View attachment "hci-tester_auto.log" of type "text/plain" (4893 bytes)